help please - lost power to cigar lighter , dome light , map light and more 1972 dart
yes 20 amp fuse , also at least 17 years old . i have not replaced that one as long as owning car .
The pump should have a label with the max amps it should draw, and the voltage that current was measured at.
If its drawing more current than listed, it could be the motor is failing internally.
The hotter the internal wiring gets, the more current it will need.
The more load put on it, the more current it will need.
The longer it runs continuously, the warmer it will get.
Heat will speed its demise as insulation and connections start to fail.
Someone who knows more about little DC motors to correct or add to this.
I beleive that unlike a light bulb, running a motor at higher voltage may reduce the current needed for a given load.
If so, it may be better to run the pump with the engine running so its at roughly 14 volts, rather than on battery at 12.5 ish Volts.
Hopefully someone can chime in who knows if this makes sense or not.
I know its true if an AC motor is rewired for 220 from 110/115 but that's not the same as this situation.